There's a concept in Anthropology/Primitive Economics called "Gift Economy" where participants in a community gifted each other help, goods, food, and rely on b

There's a concept in Anthropology/Primitive Economics called "Gift Economy" where participants in a community gifted each other help, goods, food, and rely on being gifted back similar things in higher/lower proportions sometimes in the near future. If I'm not mistaken, Debt: the First 5000 Years and the Dawn of Everything books examined this. Your graph is a formalization of such relationship, no?